Rotary cutter for planers and jointers



April 17, 1951 A. c. SKELTON ROTARY CUTTER FOR PLANERS AND JOINTERS Filed Sept. 19, 1946 luvs/arm? FIG.5. ANDREW C. SKELTON Patented Apr. 17, 1951 UNITED STATES PATENTQFFICE,

' ROTARY CUTTER FOR PLANERS AND J OINTERS Andrew 0. Skelton, St. Louis, Mo.

Application September 19, 1946, Serial No. 697,899

4 Claims. (01. 144--221) cutter throughout the full effective length thereof and in parallelism with the axis of rotation of the cutter or cylinder. Such conventional cutters are usually held in place by a plurality of spaced set screws or clamping screws, all of which must be evenly and uniformly tightened to hold the cutter knives properly in place. These cutters are particularly difficult to adjust inasmuch as each one of the clamping screws must be tightened up uniformly as the cutter is adjusted, and in the course of such tightening action it is extremely difiicult to avoid shifting the cutter slightly and causing the cutter to take a slightly deeper cut at one end than the other. In addition, the cutter blades are frequently nicked or become dulled at various sections along the length of their cutting edges as a result of encountering hard grained portions, knots, and other non-uniformities in the Wood surface being cut thereby, and when so nicked or partially dulled the entire cutter blade must be removed for resharpening or replacement. Such cutter blades, furthermore, tend to become somewhat loosened during actual use and are frequently hurled radially outwardly under centrifugal force seriously damaging either the machine itself, the work, or the workman, as the case may be.

It is, accordingly, a primary object of the present invention to provide a unique type of rotary cutter element which is simple and economical in construction and which may be readily adjusted in its entirety so that the resharpening of nicked or dulled portions is greatly simplified and facilitated.

Itis a further object of the present invention to provide a new and improved rotary cutter element for planers and jointers which may be much more simply and accurately adjusted to take various depths of cuts, as circumstances may require.

It is an additional object of the present invention to provide a rotary cutter element of the type stated which, when in actual use and operation, will not hurl the cutting element radially outwardly under centrifugal force, if the cutter element should happen to become slightly loosened.

Andwith the above and other. objects inview,

my invention resides in the novel features of form, construction, arrangement, and combination of parts presently described and pointed out in the claims. i

In the accompanying drawings- Figure 1 is a fragmentary perspective view of a planer and jointer with the tables drawn away to show a cutter element or cylinder constructed in accordance with and embodying the present invention;

Figure 2 is a top plan view of the cutter element or cylinder of the present invention;

Figure 3 is a fragmentary sectional view of the cutter element taken along line 33 of Figure 2;

Figure 4 is an enlarged perspective view of one of the cutting bits formin a part of the present invention; and

Figure 5 is a fragmentary top plan View of a modified form of cutter element constructed in accordance with and embodying the present invention.

Referring now in more detail, and by reference characters to the drawings, A designates a planer and jointer having a cutter head I provided With transversely aligned upstanding bearings 2, 3, for receiving a cutter shaft 4 which, in turn, projects through and beyond the bearing 3 and is preferably connected directly to a shaft mounted motor 5. It will, of course, be understood in this connection that the shaft 4 may be driven directly through gears, belt-and-pulley, or any other conventional driving mechanism. Pinned, keyed, or otherwise rigidly mounted upon the shaft 4 is a cutter cylinder 1' preferably forged from heat treated alloy steel and provided with a plurality of radially extending hexagonal recesses 8 arranged in a spirally extending uniformly spaced series around the outer peripheral surface of the cutter I, each such recess being counter-bored in the region of its bottom wall in the formation of a clearance-portion c. It will be apparent, by reference to Figure 2, that each succeeding recess 8 is spaced slightly rearwardly and to one side of the next preceding recess and yet overlaps in the sense that one corner :0 is disposed behind, and within the path of, the adjacent corner y of the next preceding recess 8. The recesses are, in effect, arranged in four identical spirally extending series so that along the transverse plane of the center line of any one recess 8 there will be three other identical recesses 8 respectively disposed at intervals, as best seen in Figure 3.

Located adjacent to, and ahead of, each recess 8 (reference-being had to the direction ofin place.

rotation of the cutter element 1) is an arcuate recess 9 having a back wall I parallel to the walls of the recess 8, and threadedly mounted in and extending through the wall ID for projection into the recess 8 is a clamping screw II.

Sized for snug fitting slidable disposition within each of the hexagonal recesses 8 is an hexagonal tool bit l2 having a short shank portion I3 and a relatively long cutter portion I4, three sides of which are co-planar with the corresponding side portions of the shank so as to fit tightly against the walls of the recess 8, the fourth side of the cutter portion I4 extending through the cen- 'ter line of the recess substantially co-incident with the radial plane of the cutter element or cylinder I. At its upper end, the cutter section I4 is ground off to a desired rake angle as at I5 to provide a straight, sharp cutting edge I6. The cutting edge I6 is precisely parallel with the longitudinal axis of the cutter element or cylinder 1, all as best seen in Figure 4.

Disposed within each of the recesses 8 for cooperation with each tool bit I2 is a small rectilinear clamping block I! substantially shorter in height than the height of the cutter section I4 of the bit I 2 and being provided in one of its lengthwise extending faces with an arcuate milled groove or channel I8 for slidably receiving the end of the clamping screw II.

Formed in the base I9 of the planer and jointer A, directly beneath the bearings 2, 3, is a cross beam 20 having a machined upper horizontal reference-face 2| disposed precisely in downwardly ,spaced parallel relation to the axial line of the shaft 4 for receiving a precisely machined tool steel gauge block 22 which has a height such that when resting upon the reference-face 2! its upwardly presented face 23 will be precisely located at a predetermined distance from the center line or axis of the shaft 4, such distance being greaterthan the radius of the cutter element or cylinder I by an amount equal to the depth of cut desired. In other words, when the gauge block 22 is placed upon the reference-face 2|, directly beneath one of the tool bits I2, and the clamping screw I I associated therewith loosened, the tool bit will drop down to contact the upper face 23 of the gauge block 22 and the clamping screw II may thereupon be tightened forcing the clamping block I! against the cutting tool I2 and thereby holding the latter securely It will be noted that the clamping screw I I can be tightened while the cutting edge I6 is resting against the upper face 23 of the gauge block 22, and will not tend to move out of adjustment while bein clamped. The gauge block 22 may then be moved laterally a short distance and the next cutter rotated down into place and the adjustment operation repeated. In this manner, each cutter may be successively adjusted so that its cutting edge I6 is in precise radial adjustment with respect to the axis or center line of the cutter element or cylinder I. It will, of course, be evident that after all the, cutting bits I2 have been adjusted the gauge block may be removed to a suitable place of storage. In order to provide various depths of cuts, a. plurality of gauge blocks of different height may be provided so that the cutting edges I6 of the bits I2 will project a greater or lesser amount, as may be required, for different kinds of Work.

It should also be noted that the shank portion I3 of each tool bit I2, substantially overhangs the inwardly projecting end of the clamping screw II. Consequently, the tool bit I2 will be prevented from flying completely out of the recess, even though the clamping screw I I should become somewhat loosened. It is true that the clamping block Il may be accidentally hurled outwardly, but since the latter is of relatively light metal and is small in size, it will do comparatively little, if any, damage as compared with the sharpened tool bit I2, or the even larger conventional cutting knives presently in use.

If desired, a modified form of cutter element or cylinder I may be provided, substantially similar to the previously described cutter element or cylinder 1, and likewise provided withhexagonal recesses 8 arranged in a somewhat different overlapping consecutive series such that the cutting edge I6 of every other tool bit I2 lies in the same axial line extending lengthwise of the outer peripheral surface of the cutter element or cylinder I.

Cutters constructed in accordance with the present invention may readily be removed and sharpened, as any one or more of them becomes dulled, in a simple and convenient manner. For instance, if a particular piece of wood being planed should happen to have a small knot or accidentally imbedded piece of metal, it would produce a nick in the cutting edges of the cutter.

- It is only necessary to remove from one to four of the cutting bits for resharpening and resetting,

whereas in the conventional cutter it would be necessary to entirely remove all of the cutter blades. It has also been found that cutters constructed in accordance with the present invention render planers and jointers much more flexible in application and more adaptable to a larger range of wood cutting operations. For example, certain selected cutter bits may be adjusted to a greater or lesser depth of out than other cutter bits, with the resultant production of grooves of varying depths. Finally, cutters constructed in accordance with the present invention effect a much smoother and much more uniform cutting action because of the more or less continuous spirally arranged disposition of the cutting edges. In the conventional type of cutters, having a plurality of axially extended long blades or'knives, there is a momentary impact against the work as each knife comes into cutting contact and, regardless of the rotational speed, this successive series of impacts sets up vibration in the machinery and in the work, tending to produce minute irregularities in the surface being formed. Sometimes this result becomes so pronounced that a piece of wood coming off of a planer and jointer will show large readily visible transverse striations. Cutters constructed in accordance with the present invention avoid this result, inasmuch as one or more cutting bits is always in contact With the work at all times.

It should be understood that changes and modifications in the form, construction, arrangement, and combination of the several parts of the cutter for planers and jointers may be made and substituted for those herein shown anddescribed without departing from the nature and principle of my invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

l. For use with a planer and jointer, a cutter comprising a cylinder having a plurality of radial hexagonal recesses arranged in a spiral series around the outer face thereof, a radially projecting hexagonal cutting bit removably mounted in each recess and having an enlarged shank portion at its lower end, and clamping means associated with each recess for releasably securing the cutting bit withinthe recess, said clamping means including a clamping block disposed entirely within the recess and having a lengthwise extending groove, and a clamping screw threadedly mounted in and projecting through the cutter, said screw having an inner end normally engaged in said groove for forcing the block retentively against the bit and being adapted, the groove engaging end of the clamping screw being or" such length, even when loosened and partially withdrawn, to engage the shank portion in stopforming manner if the bit tends to move radially outwardly from the recess under influence of centrifugal force when the cutter is in operation.

2. For use with planers and jointers, a cutter comprising a cylinder having a plurality of radial hexagonal recesses arranged in spaced series around the outer face thereof, a radially projecting hexagonal cutting bit removably mounted in each recess, said bits being comprised of a cutter portion having a side extending through the center line of the recess and an enlarged shank portion at its lower end, a clamping block disposed entirely within the recess and having a longitudinal groove on one side thereof, and a clamping screw threadably mounted in and extending through the cutter into each of said recesses for engagement with the longitudinal groove in said clamping blocks, whereby adjustment of said screw will force said block retentively against the said side of the cutter portion of the bit and being adapted, even when loosely and partially withdrawn, to engage the shank portion in stopforming manner if the bit tends to move radially outwardly from the recesses under influence of centrifugal force when the cutter is in operation.

3. For use with planers and jointers, a cutter comprising a cylinder having a plurality of radial hexagonal recesses arranged in a spaced series around the outer face thereof, a radially projecting hexagonal cutting bit removably mounted in each recess, said bits being comprised of a cutter portion having a side extending through the center line of the recess and an enlarged shank portion at its lower end, a clamping block disposed entirely within the recess and having a longitudinal groove on one side thereof, and a clamping screw threadably mounted in and extending through the cutter into each of said recesses for engagement with the longitudinal groove in said clamping blocks, whereby adjustmentof said screw will force said block retentively against the said side of the cutter portion of the bit, said shank portion of the bit being disposed in overhanging relationship to that portion of the screw projecting into said recesses so that when said screw is loosely and partially withdrawn it will engage the shank portion in stop-forming manner if the bit tends to move radially outwardly from the recesses under influence of centrifugal force when the cutter is in operation.

4. For use with planers and jointers, a cutter comprising a cylinder having a plurality of radial hexagonal recesses arranged in a spaced. series around the outer face thereof, a radially projecting hexagonal cutting bit removably mounted in each recess, said bits being comprised of a cutter portion having a side extending through the center line of the recess and an enlarged shank portion at its lower end, a clamping block disposed entirely within the recess and having a longitudinal groove on one side thereof, and a clamping screw threadably mounted in and extending through the cutter into each of said hexagonal recesses, the outer ends of said clamping screw being disposed in arcuate recesses spaced rearwardly from each of said hexagonal recesses to facilitate adjustment of said screws, the inner end of said clamping screw engaging the shank portion in stop-forming manner if the bit tends to move radially outwardly from the recesses under influence of centrifugal force when the cutter is in operation.

ANDREW C. SKELTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 416,869 Smith Dec. 10, 1889 542,075 Brown, E. W July 2, 1895 630,081 Brown, H. S Aug. 1, 1899 833,261 Tardif Oct. 16, 1906 872,890 Blood Dec. 3, 959,328 Eynon May 24, 1910 994,264 MacKay June 6, 1911 1,204,829 Taylor Nov. 14, 1916 1,282,285 Plank Oct. 22, 1918 1,428,308 Wiard Sept. 5, 1922 1,705,994 Peterson Mar. 19', 1929 

